ICL 8.0: Anatomy of the Neck Flashcards
where is the hyoid bone located?
between the mandible and hyoid cartilage
many ligaments and muscles etc. attach to it!
what are the bony landmarks of the hyoid bone?
the whole bone is horseshoe shaped
there are 2 greater horns and 2 lesser horns –> the lesser horns stick up vertically
which cervical vertebrae are atypical?
C1
C2
C7
what are the characteristics of the atlas?
- no body; instead it has 2 lateral masses
the two lateral masses are connected together anteriorly by the anterior arch and posteriorly by the posterior arch
- no spinous process
- transverse formamen (vertebral artery passes through)
- transverse ligament that connected the lateral masses
what is the atlantooccipital joint?
the superior articular surface of the atlas articulates with the occipital condyles of the skull to form the atlantoocipital joint
this allows for flexion and extension aka the “yes” motion
what are the characteristics of the axis?
- dens/odontoid process
- it does have a body!
- bifurcated spinous process
- transverse foramen
what is the atlantoaxial joint?
there’s actually 3 atlantoaxial joints! two lateral and one median
the median atlantoaxial joint is where the dens articulates with the atlas and allows for your head to rotate and make the “no” motion
the lateral atlantoaxial joints are you normal facet joint
what is a C2 fracture?
Hangman’s fracture
usually due to hyperextension that leads to a pars interacticularis fracture
what are the characteristics of normal cervical vertebrae?
C3-C6 are typical cervical vertebrae
- body
- pedicles
- transverse processes with transverse foramen
the transverse processes are made up of the anterior and posterior tubercles
- inferior and superior articular processes
- uncinate process
what is special about the transverse process of C6?
the anterior tubercle of C6 is called carotid tubercle
the common carotid artery passes next to the carotid tubercle
so in patients with high blood pressure or HR, you can massage the carotid artery into the carotid tubercle to reduce HR and BP
what are the characteristics of C7?
- spinous process is NOT bifurcated = vertebra prominent
- NO anterior tubercle of the transverse process
patients who do have an anterior tubercle can develop thoracic outlet syndrome from the tubercle compressing on the lower trunk of the brachial plexus
what is the platysma?
a superficial muscle in the neck; like if you strain your neck that’s the muscle you’re seeing
it attaches proximally to the clavicle and distally to the mandible
what is the action and innervation of the platysma?
cervical branch of the facial nerve
it’s involved with making facial expressions
also people hypothesize that maybe when it contracts it prevents veins from collapsing by shielding them from negative pressure; total speculation
what do you need to be careful with when it comes to incisions involving the platysma?
during suturing skin incision or wounds in the neck, the cut platysma needs to be sutured separately to prevent gaping of the wound and stretching of the skin scar
what are the two main veins in the neck?
- external jugular vein
2. anterior jugular vein
what is the course of the external jugular vein?
it starts from the union of the posterior division of the retromandibular vein with the posterior auricular vein
it then drains into the subclavian vein
what is the course of the anterior jugular vein?
it starts by the confluence of submandibular and submental veins
it runs close to the midline of the neck on each side
the right and left anterior veins connect at their proximal ends via the jugular arch which then drains into the external jugular vein (which then drains into the subclavian vein)
what are engorged neck veins pathological for?
engorged neck veins are common signs for heart disease such as, right-sided heart failure, cardiac tamponade, tricuspid valve disease, pulmonary hypertension
during what procedure should you be worried about piercing the jugular arch?
tracheostomy
the jugular arch is in your way during tracheostomy and may cause bleeding
the jugular arch connects the left and right anterior jugular veins
what are the 4 cutaneous nerves of the neck? what are their nerve roots?
- great auricular (the biggest) (C2,C3)
- transverse cervical (C2, C3)
- lesser occipital (C2)
- supraclavicular (C3,C4)
what is a good location to perform cervical plexus nerve block?
the cutaneous branches of the cervical plexus outcrop at the middle of the posterior border of the sternocleidomastoid muscle
this means that the great auricular, lesser occipital, supraclavicular and transverse cervical nerves all come out at this spot to do their cutaneous innervation of the neck so it’s a great spot to do a cervical plexus nerve block since they’re all there!
inflammation of the gall bladder causes referred pain in the right shoulder? why?
the gall bladder and the cutaneous sensation of the right shoulder both have C3/C4 roots
so since the brain doesn’t really process visceral pain from organs such as the gallbladder, this pain is instead interpreted as right shoulder pain via the supraclavicular nerve
what are the borders of the anterior triangle of the neck?
Mid-line of the neck
Lower border of the body of the mandible
Anterior border of sternocleidomastoid
what are the borders of the posterior triangle of the neck?
posterior border of the SCM
middle 1/3 of the clavicle
anterior border of trapezius
what is the sternocleidomastoid origin, insertion, innervation?
there are two heads of the muscle:
the sternal head comes from the manubrium while the clavicular head comes from the medial 1/3 of the clavicle –> the depression between the two is know as lesser supraclavicular fossa which contains supraclavicular lymph node
they insert at the mastoid process and the lateral 1/3 of the superior nuchal line
they’re innervated by the spinal accessory nerve
what is the action of the sternocleidomastoid?
acting alone it tilts the head to ipsilateral shoulder but rotates the chin to the contralateral side
but acting together it extends and flexes the neck
what is Torticollis?
aka Wryneck
it’s a congenital or spasmodic contracture of the SCM that result in deformity of the head and neck
persistent spasmodic contraction of SCM my require division of spinal accessory nerve
what are Virchow lymph nodes?
between the sternal and clavicular heads of SCM there one/multiple lymph nodes and on the left side of the body they’re specifically called Virchow lymph nodes
they drain the abdominal structures and are enlarged in abdominal malignancy
on the right side of the body, these lymph nodes drain thoracic content structures and are enlarged in thoracic malignancy
what is the clinical significance of the lesser supraclavicular triangle?
it’s the opening between the clavicular and sternal head of the sternocleidomastoid
it’s where you can access external jugular vein for central lines!
what are the subdivisions of the anterior triangle?
- muscular triangle
- carotid triangle
- digastric triangle
- submental triangle
what are the borders of the muscular triangle?
anterior: mid-line of the neck
posterior: anterior border of SCM
superior: superior belly of omohyoid muscle
what are the contents of the muscular triangle?
- all the infra hyoid muscles!
sternohyoid, superior belly of the omohyoid, sternothyroid, and thyrohyoid
- viscera of the neck
larynx, pharynx, trachea, esophagus, thyroid and parathyroid gland
what are the infrahyoid muscles?
LAYER 1
1. omohyoid (superior and inferior belly)
- sternohyoid
SECOND LAYER
1. sternothyroid
- thyrohyoid
they all depress the hyoid bone
what is the innervation of the infrahyoid muscles?
they are all supplied by the ansa cervicalis
EXCEPT the thyrohyoid which is innervated by C1
what are the boundaries of the carotid triangle?
anterior: superior belly of Omohyoid
posterior: anterior border of SCM
superior: posterior belly of digastric
the floor of the carotid triangle is the superior and middle constrictor muscles of the pharynx
what are the contents of the carotid triangle?
- common, external and internal carotid arteries
- internal jugular vein
- the last 4 cranial nerves
- ansa cervicalis
- cervical sympathetic trunk
what are the last 4 cranial nerves?
- glossopharyngeal nerve
- vagus nerve
- spinal accessory nerve
- hypoglossal nerve
describe the common carotid artery in the carotid triangle
the right common carotid arises from the brachiocephalic trunk
the left common carotid arises from the arch of the aorta
the common carotid arteries then dilate at the distal ends to form the carotid sinus where it divides into two terminal branches; the external and internal carotid arteries at the upper border of thyroid cartilage
no other branches in the neck!!
where can you feel the common carotid artery pulse? why is this significant?
common carotid pulsation can be felt anterior to the anterior border of SCM and below the angle of the mandible
this is where you can listen for arterial bruit!!
what is hypersensitive carotid sinus syndrome?
the carotid sinus has baroreceptors that monitor BP
some individuals have hypersensitive carotid sinus in which sudden movements of the head or pressure over the carotid sinus may evoke vagal reflex of slowing the heart rate with concomitant drop in blood pressure which may make the individual faints
which receptors are in the carotid body?
chemoreceptors for O2 and CO2
if the level of CO2 and O2 changes, the phrenic and intercostal nerves are responsible for breathing and will change your breathing to bring gas levels back to normal
where does the external carotid artery start and end?
the external carotid artery is a branch of the common carotid artery
it starts at the carotid sinus as one of the two terminal branches of the common carotid (the other is the internal carotid artery)
it ends at the neck of the mandible by giving two terminal branches = the maxillary and superficial temporal arteries
what are the important branches of the external carotid artery?
- superior thyroid
- lingual
- facial
- occipital (pierces the trapezius)
the external carotid artery is more surgically accessible than some of it is deep branches
therefore, it is easier to ligate external carotid to control bleeding from one of its deep less accessible branches. It is ligated in the carotid triangle anterior to the anterior border of the sternocleidomastoid
where does the internal jugular vein start and end?
it starts at the jugular foramen in the skull as a continuation of sigmoid sinus
it ends behind the sternoclavicular joint by joining the subclavian vein to form the brachiocephalic vein
it drains the brain, head and neck